Electronic devices including solid semiconductor dies

ABSTRACT

Electronic devices including a layer of polymeric material and solid semiconductor dies partially embedded in the layer are provided. The dies have first ends projecting away from the first major surface of the layer. The electronic devices can be formed by sinking the first ends of the dies into a major surface of a liner. A flowable polymeric material is filled into the space between the dies and solidified to form the layer of polymeric material. The first ends of the dies are exposed by delaminating the liner from the first ends of the dies. Electrical conductors are provided on the layer to connect the first ends of the dies.

TECHNICAL FIELD

The present disclosure relates to electronic devices (e.g.,thermoelectric devices) including solid semiconductor dies, and methodsof making and using the same.

BACKGROUND

Solid semiconductor dies are available to be integrated into variouselectronic devices. For example, a ceramic thermoelectric module can bemade by placing an array of solid thermoelectric dies between twoparallel ceramic substrates. Electrodes can be formed on the ceramicsubstrates to electrically connect legs of the thermoelectric dies bysoldering or brazing, which is typically a manual assembly process.

SUMMARY

There is a desire to fabricate electronic devices including solidsemiconductor dies in a large-area format and cost-effective ways.Briefly, in one aspect, the present disclosure describes a methodincluding providing an array of solid semiconductor dies each extendingbetween a first end and an opposite, second end thereof, sinking thefirst ends of the dies into a major surface of a first liner, filling aflowable polymeric material onto the major surface of the first liner,and solidifying the polymeric material to form a layer of polymericmatrix material. The array of solid semiconductor dies are at leastpartially embedded in the layer. The method further includesdelaminating the first liner from the first ends of the dies to exposethe first ends of the dies, and electrically connecting the exposedfirst ends of the dies.

In another aspect, the present disclosure describes an electronic filmdevice including a layer of polymer matrix material, the layer havingopposite first and second major surfaces, and an array of solidsemiconductor dies being at least partially embedded in the layer. Thedies each extend between a first end and a second end thereof The firstends project away from the first major surface of the layer. A firstelectrical conductor extends on the first major surface of the layer toconnect the first ends of the dies.

In another aspect, the present disclosure describes a flexiblethermoelectric module including a layer of flexible polymer material,the layer having opposite first and second major surfaces, and an arrayof solid thermoelectric dies being at least partially embedded in thelayer. The dies each extend between a first end and a second endthereof. Both ends are exposed from the layer of flexible polymermaterial. At least one of the first and second ends projects away fromthe layer. A first electrical conductor extends on the first majorsurface of the layer to connect the first ends of the array of dies. Asecond electrical conductor extends on the first major surface of thelayer to connect the second ends of the array of dies.

Various unexpected results and advantages are obtained in exemplaryembodiments of the disclosure. One such advantage of exemplaryembodiments of the present disclosure is that electronic devicesincluding solid semiconductor dies can be fabricated in a large-areaformat and cost-effective ways. The solid semiconductor dies can beintegrated with a flexible polymer layer, which can result in flexibleelectronic devices. The processes of fabricating flexible electronicdevices can include a roll-to-roll (R2R) process, which can effectivelyreduce the thickness of electronic film devices, provide flexible,large-area electronic devices, and reduce the processing cost.

Various aspects and advantages of exemplary embodiments of thedisclosure have been summarized. The above Summary is not intended todescribe each illustrated embodiment or every implementation of thepresent certain exemplary embodiments of the present disclosure. TheDrawings and the Detailed Description that follow more particularlyexemplify certain preferred embodiments using the principles disclosedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description of various embodiments of the disclosurein connection with the accompanying figures, in which:

FIG. 1 is a cross sectional view of an electronic device, according toone embodiment of the present disclosure.

FIG. 2A is a cross sectional view of a pre-structured tooling, accordingto one embodiment of the present disclosure.

FIG. 2B is a cross sectional view of the pre-structured tooling of FIG.2A with any array of dies disposed therein, according to one embodimentof the present disclosure.

FIG. 2C is a cross sectional view of the dies of FIG. 2B to betransferred from the pre-structured tooling onto an adhesive tape,according to one embodiment of the present disclosure.

FIG. 2D is a cross sectional view of the dies of FIG. 2C disposed on theadhesive tape, according to one embodiment of the present disclosure.

FIG. 2E is a cross sectional view of the dies of FIG. 2D to betransferred from the adhesive tape to a first liner, according to oneembodiment of the present disclosure.

FIG. 2F is a cross sectional view of the dies of FIG. 2E where one endof the dies sinks into a first liner, according to one embodiment of thepresent disclosure.

FIG. 3A is a cross sectional view of the dies of FIG. 2F where anotherend of the dies sinks is in contact with a second liner, according toone embodiment of the present disclosure.

FIG. 3B is a cross sectional view of the dies of FIG. 3A where the spacebetween the first and second liners is filled with a polymer material,according to one embodiment of the present disclosure.

FIG. 3C is a cross sectional view of the dies of FIG. 3B where thepolymer material is solidified to form a polymer layer, according to oneembodiment of the present disclosure.

FIG. 3D is a cross sectional view of the dies of FIG. 3C partiallyembedded in the polymer layer, according to one embodiment of thepresent disclosure.

FIG. 3E is a cross sectional view of the dies of FIG. 3D where the firstends of the dies are electrically connected, according to one embodimentof the present disclosure.

FIG. 3F is a cross sectional view of the dies of FIG. 3E where thesecond ends of the dies are electrically connected, according to oneembodiment of the present disclosure.

FIG. 4A is a cross sectional view of the dies of FIG. 2F with one endsinking into the first liner where the space between the dies is filledwith an ink material by inkjet printing, according to one embodiment ofthe present disclosure.

FIG. 4B is a cross sectional view of the dies of FIG. 4A where the spacebetween the dies is filled with an ink material by inkjet printing,according to one embodiment of the present disclosure.

FIG. 5A is a cross sectional view of the dies of FIG. 2F with one endsinking into the first liner where the space between the dies is filledwith a polymer material by coating, according to one embodiment of thepresent disclosure.

FIG. 5B is a cross sectional view of the dies of FIG. 5A where thepolymer material is solidified by curing from one side to form a polymerlayer, according to one embodiment of the present disclosure.

FIG. 5C is a cross sectional view of the dies of FIG. 5B with uncuredpolymer material to be removed, according to one embodiment of thepresent disclosure.

FIG. 5D is a cross sectional view of the dies of FIG. 5C where theuncured polymer material is washed away, according to one embodiment ofthe present disclosure.

FIG. 5E is a cross sectional view of the dies of FIG. 5E where the firstliner is delaminated from the first ends of the dies, according to oneembodiment of the present disclosure.

FIG. 6A is a cross sectional view of the dies of FIG. 2F where aconductive low-surface energy material is coated on the second ends ofthe dies, according to one embodiment of the present disclosure.

FIG. 6B is a cross sectional view of the dies of FIG. 6A the spacebetween the dies is filled with a polymer material by coating, accordingto one embodiment of the present disclosure.

FIG. 6C is a cross sectional view of the dies of FIG. 6B where thepolymer material de-wets from the second ends of the dies, according toone embodiment of the present disclosure.

FIG. 6D is a cross sectional view of the dies of FIG. 6C where thepolymer material is solidified to form a polymer layer, according to oneembodiment of the present disclosure.

FIG. 6E is a cross sectional view of the dies of FIG. 6D where the firstliner is delaminated from the first ends of the dies, according to oneembodiment of the present disclosure.

FIG. 6F is a cross sectional view of the dies of FIG. 6E where thesecond ends of the dies are electrically connected, according to oneembodiment of the present disclosure.

FIG. 6G is a cross sectional view of the dies of FIG. 6F where the firstends of the dies are electrically connected, according to one embodimentof the present disclosure.

In the drawings, like reference numerals indicate like elements. Whilethe above-identified drawing, which may not be drawn to scale, setsforth various embodiments of the present disclosure, other embodimentsare also contemplated, as noted in the Detailed Description. In allcases, this disclosure describes the presently disclosed disclosure byway of representation of exemplary embodiments and not by expresslimitations. It should be understood that numerous other modificationsand embodiments can be devised by those skilled in the art, which fallwithin the scope and spirit of this disclosure.

DETAILED DESCRIPTION

For the following Glossary of defined terms, these definitions shall beapplied for the entire application, unless a different definition isprovided in the claims or elsewhere in the specification.

Glossary

Certain terms are used throughout the description and the claims that,while for the most part are well known, may require some explanation. Itshould understood that:

The term “flowable polymeric material” refers to a liquid compositionsuch as an ink composition, or a molten or semi-molten polymericmaterial.

The term “liner” refers to a substrate having a major surface that isdeformable to accommodate a sinking of an end of a solid semiconductordie and is capable of forming a fluid seal between the major surface andthe end of the die.

By using terms of orientation such as “atop”, “on”, “over,” “covering”,“uppermost”, “underlying” and the like for the location of variouselements in the disclosed coated articles, we refer to the relativeposition of an element with respect to a horizontally-disposed,upwardly-facing substrate. However, unless otherwise indicated, it isnot intended that the substrate or articles should have any particularorientation in space during or after manufacture.

The terms “about” or “approximately” with reference to a numerical valueor a shape means +/− five percent of the numerical value or property orcharacteristic, but expressly includes the exact numerical value. Forexample, a viscosity of “about” 1 Pa-sec refers to a viscosity from 0.95to 1.05 Pa-sec, but also expressly includes a viscosity of exactly 1Pa-sec. Similarly, a perimeter that is “substantially square” isintended to describe a geometric shape having four lateral edges inwhich each lateral edge has a length which is from 95% to 105% of thelength of any other lateral edge, but which also includes a geometricshape in which each lateral edge has exactly the same length.

The term “substantially” with reference to a property or characteristicmeans that the property or characteristic is exhibited to a greaterextent than the opposite of that property or characteristic isexhibited. For example, a substrate that is “substantially” transparentrefers to a substrate that transmits more radiation (e.g. visible light)than it fails to transmit (e.g. absorbs and reflects). Thus, a substratethat transmits more than 50% of the visible light incident upon itssurface is substantially transparent, but a substrate that transmits 50%or less of the visible light incident upon its surface is notsubstantially transparent.

As used in this specification and the appended embodiments, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise. Thus, for example, reference to fine fiberscontaining “a compound” includes a mixture of two or more compounds.

As used in this specification and the appended embodiments, the term“or” is generally employed in its sense including “and/or” unless thecontent clearly dictates otherwise.

As used in this specification, the recitation of numerical ranges byendpoints includes all numbers subsumed within that range (e.g. 1 to 5includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).

Unless otherwise indicated, all numbers expressing quantities oringredients, measurement of properties and so forth used in thespecification and embodiments are to be understood as being modified inall instances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the foregoingspecification and attached listing of embodiments can vary dependingupon the desired properties sought to be obtained by those skilled inthe art utilizing the teachings of the present disclosure. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claimed embodiments, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Various exemplary embodiments of the disclosure will now be describedwith particular reference to the Drawings. Exemplary embodiments of thepresent disclosure may take on various modifications and alterationswithout departing from the spirit and scope of the disclosure.Accordingly, it is to be understood that the embodiments of the presentdisclosure are not to be limited to the following described exemplaryembodiments, but are to be controlled by the limitations set forth inthe claims and any equivalents thereof.

FIG. 1 illustrates a cross-sectional view of an article 100. The article100 includes a layer 10 of polymeric material having opposite first andsecond major surfaces 12 and 14. In some embodiments, the layer 10 canbe a flexible layer of polymer matrix material, which can be, forexample, a curing product of a curable polymer material. The suitablecurable polymer material may include, for example, a polyurethaneacrylate, a polydimethylsiloxane, a polyurethane rubber, a polyolefinfoam, etc. The layer 10 have a thickness of, for example, about 10microns to about 0.5 cm.

An array of solid semiconductor dies 20 is at least partially embeddedin the polymer layer 10. The solid semiconductor dies 20 each extendbetween a first end 22 and a second end 24 thereof. The first ends 22project away from the first major surface 12 of the layer 10. In someembodiments, the first ends 22 of the dies 20 project away from thefirst major surface 12 of the polymer layer 10 with a step 122. The step122 may have an average height of about 1 to about 100 microns, about 1to about 50 microns, about 1 to about 25 microns, or about 2 to about 25microns. The first ends 22 of the dies 20 are electrically connected bya first electrical conductor 32. The second ends 24 of the dies 20 areelectrically connected by a second electrical conductor 34. The array ofdies 20 can include any number (e.g., one, two, three or more) of dies.The dies 20 can be regularly or randomly arranged.

The article 100 of FIG. 1 can be an electronic device such as, forexample, a thermoelectric device, an optoelectronic device, etc., whichmay depend on the types of the solid semiconductor dies 20. In someembodiments, the solid semiconductor dies 20 may include one or morethermoelectric chips and the article 100 can be a thermoelectric device.The thermoelectric chips may be made of an n-type semiconductor material(e.g., Bi₂Te₃ or its alloys) or a p-type semiconductor material (e.g.,Sb₂Te₃ or its alloys). In some embodiments, the solid semiconductor dies20 may include one or more LED chips and the article 100 can be anoptoelectronic device.

In some embodiments, the solid semiconductor dies 20 may includeelectrical contacts (e.g., legs for thermoelectric chips) disposed onthe surfaces of at least one of the first and second ends 22 and 24. Theelectrical contacts of the dies 20 can be electrically connected, e.g.,via the first or second electrical conductors 32 and 34, to form anelectrical circuits with desired functions.

The solid semiconductor dies 20 are at least partially embedded in thelayer 10 of polymeric material. In the depicted embodiment of FIG. 1,the first and second ends 22 and 24 are at least partially exposed fromthe layer 10 of polymeric material to allow the electronic conductors 32and 34 to electrically connect the contacts on the first and second ends22 and 24, respectively.

FIGS. 2A-2F illustrate a process of fabricating the article 100 of FIG.1, according to one embodiment. A pre-structured tooling 2 is providedwith pre-defined cavities 4 on a major surface 6 thereof to receive thesolid semiconductor dies 20. The pre-structured tooling 2 can be, forexample, a patterned rotary belt, a patterned drum, etc. The placementof the solid semiconductor dies 20 into the cavities 4 can be performedby using, for example, standard “pick and place” equipment, a chipshooter, or a laser-based transfer method. Confining the solidsemiconductor dies 20 in the pre-defined cavities 4 on the tooling 2 canbe advantageous in that a) it enables precision placement even at higherspeeds, and b) it maintains absolute and relative orientation of thesolid semiconductor dies 20 on the moving tooling 2 without having totack them down.

As shown in FIG. 2B, the solid semiconductor dies 20 are disposed in thecavities 4 of the tool 2. The second ends 24 project away from the majorsurface 6. The array of solid semiconductor dies 20 is then transferredfrom the pre-structured tooling 2 to an adhesive tape 8 by contactingthe adhesive tape 8 with the second ends 24 of the dies 20, as shown inFIGS. 2C-D. The adhesive tape 8 can be pressed against the major surface6 of the pre-structured tooling 2. When the adhesive tape 8 is removedfrom the tooling 2, the dies 20 can be transferred to the adhesive tape8. The relative orientation of the dies 20 can be maintained on theadhesive tape 8 after the transfer. The adhesive tape 8 can be asubstrate coated with a “weak” adhesive such as, for example, a 3MScotch removable tape. It is to be understood that the adhesive tape 8can be any suitable holding surface (e.g., an adhesive surface, apatterned surface, etc.) that it can hold the second ends of the dies 20securely which can be easy to remove later.

A first liner 50 is then provided to contact to the first ends 22 of thedies 20, as shown in FIG. 2E. A liner described herein refers to asubstrate having a major surface that is deformable to accommodate asinking of an end of a solid semiconductor die and is capable of forminga tight seal between the major surface and the end of the die. Inaddition, the major surface of the liner may have a low surface energysuch that a polymeric coating and the dies disposed thereon can bereleasable therefrom.

In the depicted embodiment of FIG. 2E, the first liner 50 includes asurface layer 52 disposed on a substrate 54 thereof. The surface layer52 and the substrate 54 can be made of different materials where thesurface layer 52 has a lower melting temperature than the substrate 54.In some embodiments, the first liner 50 can be heated to certaintemperatures under which the surface layer 52, not the substrate 54, canbe at least partially melt or softened to allow the first ends 22 of thedies 20 to sink into the surface layer 52. The substrate 54 can sustainits stiffness under such temperatures and serve as a stop layer to holdthe surface layer 52 and the dies 20 in position. In some embodiments,the first liner may include a layer of polyethylene phthalate and alayer of polyethylene.

In some embodiments, after the first ends 22 of the dies 20 sinking intothe major surface of the first liner 50, the major surface can bere-solidified to anchor the array of dies thereon. For example, thefirst liner 50 can be cooled down, e.g., at room temperature, tore-solidify the surface layer 52. After the array of dies 20 arepositioned and secured on the first liner 50, the adhesive tape 8 can beremoved and the dies 20 are transferred from the adhesive tape 8 to thefirst liner 50, as shown in FIG. 2F.

In the embodiment shown in FIG. 3A, a second liner 60 is provided tocontact to the second ends 24 of the dies 20. Similar to the first liner50, the second liner 60 includes a surface layer 62 disposed on asubstrate 64 thereof. The surface layer 62 and the substrate 64 of thesecond liner 60 can be made of different materials where the surfacelayer 62 has a lower melting temperature than the substrate 64. In someembodiments, the second liner 60 can be heated to certain temperaturesunder which the surface layer 62, not the substrate 64, can be at leastpartially melt or softened to allow the second ends 24 of the dies 20 tosink into the surface layer 62. The substrate 64 can sustain itsstiffness under such temperatures and serve as a stop layer to hold thesurface layer 62 and the dies 20 in position.

With the first and second ends 22 and 24 of the dies 20 beingrespectively positioned into the opposite liners 50 and 60, aparallel-plate-like structure is created. The distance between theopposite liners 50 and 60 is substantially determined by the height ofthe dies 20. The space 10′ between the first and second liners 50 and 60is then filled with a flowable polymeric material 10 a′, as shown inFIG. 3B. The first and second ends 22 and 24 of the dies 20 areprotected from the polymeric material 10 a′.

In some embodiments, the polymeric material 10 a′ can be provided toflow into the space 10′. In some embodiments, a liquid, melt, orsemi-molten polymeric material 10 a′ can be provided into the space 10′,for example, by dispensing, injecting, printing, etc. In someembodiments, the polymeric material 10 a′ can be a liquid with lowviscosity. When the low viscosity liquid approaches an edge of theparallel-plate-like structure, it can flow into the space 10′ bycapillary pressure. As long as there is continuous supply of the liquid,the liquid front can proceed to completely fill the interstitialsbetween the dies 20. The capillary flow can be aided by the presence ofdie array 20 between the liners 50 and 60, which form localized fluidchannels. The rate of capillary filling may be determined by rheology,surface energetics, height of the dies and their relative orientation,etc.

Upon complete filling the space 10′, the flowable polymeric material 10a′ can be solidified via, for example, thermal or radiation curing(e.g., UV curing), to form a layer 10 a of polymeric material. FIG. 3Cis a cross sectional view of the parallel-plate-like structure of FIG.3B where the polymeric material is solidified to form the layer 10 a. Itis to be understood that the flowable polymeric material can besolidified by any other suitable methods or processes.

After the formation of the layer 10 a, the first and second liners 50and 60 are delaminated from the dies 20 and the layer 10 a. It is to beunderstood that the liners 50 and 60 may include any suitable materialsand configurations as long as that (i) the major surfaces are deformableto accommodate a sinking of an end of a solid semiconductor die and (ii)the liners can be delaminated from the dies and the polymeric layer.FIG. 3D is a cross sectional view of the dies 20 partially embedded inthe layer 10 a of polymeric material. The first and second ends 22 and24 of the dies 20 are exposed after the removal of the first and secondliners 50 and 60. In some embodiments, the first and/or second ends canproject away from the respective major surface 12 or 14 of the layer 10a.

The first electrical conductor 32 is provided to electrically connectthe contacts on the first ends 22 of the dies 20; the second electricalconductor 34 is provided to electrically connect the contacts on thesecond ends 24 of the dies 20, as shown in FIGS. 3E-3F. The electricalconductors 32 and 34 can extend between adjacent ends of the dies 22 or24 on the respective major surfaces 12 and 14 of the layer 10 a. Theelectrical conductors 32 and 34 can be formed on the layer 10 a by anysuitable methods. In some embodiments, the smoothness and flatness ofthe layer 10 a can facilitate the use of, for example, a printingmethod, a laminating method, etc.

In the embodiment depicted in FIG. 3F, the solid semiconductor dies 20include an array of n-type and p-type thermoelectric chips which areelectrically connected to form a thermoelectric circuit (e.g., athermoelectric generator). A direct electric current can flow in thecircuit when there is a temperature difference between the opposite ends22 and 24 of the thermoelectric chips 20.

The electrical conductor 32 or 34 can be formed from a deposited orprinted metal pattern. The metal can include, for example, copper,silver, gold, aluminum, nickel, titanium, molybdenum, the combinationsthereof, etc. In some embodiments, the metal pattern can be formed bysilk screen printing using a metal-composite ink or paste. In otherembodiments, the metal pattern can be formed by flexographic printing orgravure printing. In other embodiments, the metal pattern can be formedby ink jet printing. In other embodiments, the metal pattern can beformed by electroless deposition. In other embodiments, the metal can bedeposited by means of sputtering or CVD deposition followed byphotolithographic patterning. The metal thickness can range, forexample, between 1 micron and 100 microns. In some embodiments, theelectrical conductors can be printed onto the flat surfaces of thepolymer layer 10 a to connect the respective ends of the dies 20. Insome embodiments, the electrical conductors can be formed by laminatinga patterned metal tape (e.g., Cu tape), or by electroless deposition ofmetals. It is to be understood that the electrical conductors can beformed by any suitable methods to electrically connect the respectiveends of the dies 20.

In some embodiments, the end surface of the semiconductor dies 20 can befurther cleaned before providing the electrical conductors 32 and 34thereon. Methods of cleaning can include, for example, solvent rinse,acid rinse with ultrasound, abrasion with sandpaper or by sandblasting,high pressure water spray, sputter clean, plasma clean, etc. Suchcleaning can improve the quality of electrical contacts.

When the dies 20 have the first ends 22 positioned into the first liner50, as shown in FIG. 2F, a polymer layer can be formed directly on thefirst liner 50 to fill the space 10′ thereon. In the embodiment depictedin FIG. 4A, the interstitials 26 between the solid semiconductor dies 20are filled with an ink material 10 b′ dispensed by inkjet printing 3.Driven by a capillary pressure, the ink 10 b′ may travel a certaindistance from each dispensing site, which may depend on rheology,surface energetics and/or die geometry. Fresh ink can be dispensed atperiodic sites along the width of the substrate to ensure a continuouscoverage of the interstitials 26 between the dies 20.

In some embodiments, the ink can be provided in a suitable amount withsuitable properties such that while the ink advances in thespaces/interstitials between the dies 20, it can be confined to below alevel defined by the upper edges of the dies 20 due to pinning effects,as shown in FIG. 4B. The ink 10 b′ may not flow onto or cover the secondends 24 of the dies 20. Upon complete filling, the first liner 50 andthe supported dies 20 and ink 10 b′ can be passed through a laminationnip to flatten the ink surface profile before the solidification step.

In the embodiment depicted in FIG. 5A, a flowable polymer material 10 c′is directly coated, via a coating apparatus 5, onto the first liner 50to fill in the interstitials 26 between the dies 20. The polymermaterial 10 c′ can be coated to completely cover the dies 20, i.e., thelevel 12′ of the polymer material 10 c′ being higher than the ends 24 ofthe dies 20. The polymer material 10 c′ is then cured by radiation 7from the backside of the dies 20 to form a layer 10 c of polymericmaterial. The radiation 7 can be, for example, a collimatedUV-illumination. The dies 20 can block the radiation from curing theportion 14′ of polymer material on the second ends 24 of the dies 20.The uncured material 14′ can be removed (e.g., by washing) to expose thesecond ends 24 of the dies 20 after the formation of the layer 10 c.After the removal of the uncured material 14′, an indent 142 can beformed from the second major surface 14 of the layer 10 c to the secondends 24 of the dies 20 as shown in FIG. 5D. The indent 142 may have adimension of, for example, about 1 to about 100 microns, about 1 toabout 50 microns, about 1 to about 25 microns, or about 2 to about 25microns. After the removal of the first liner 50, the first ends 22 ofthe dies 22 can be exposed. The first ends 22 project away from thefirst major surface 12 of the layer 10 c with a step 122. The step 122may have a dimension of, for example, about 1 to about 100 microns,about 1 to about 50 microns, about 1 to about 25 microns, or about 2 toabout 25 microns.

In the embodiment depicted in FIG. 6A, an electrically conductivecoating 36 is provided on the second ends 24 of the dies 20. Theelectrically conductive coating 36 can be made of a low-surface energymaterial such as, for example, a silicone-based silver ink. Any suitablemethods can be used to form the electrically conductive coating 36 suchas, for example, by flexographically printing the top surface of thedies using a flat stamp. A flowable polymer material 10 d′ can becoated, via a coating apparatus 5, onto the first liner 50. The coatedpolymer material 10 d′ can de-wet from the conductive coating 36 when itapproaches the ends 24 of the dies 20, as shown in FIGS. 6B-C. The level12′ of the coated polymer 10 d′ can be substantially equal or lower thanthe conductive coating 36. The polymer material 10 d′ is then solidifiedto form a polymer layer 10 d, as shown in FIG. 6D. The first liner 50 isremoved to expose the first ends 22 of the dies 20, which areelectrically connected by the first electrical conductor 32, as shown inFIG. 6G. The electrically conductive coating 36 on the second ends 24 ofthe dies are electrically connected by the second electrical conductor34, as shown in FIGS. 6F-6G. In some embodiments, when the electricallyconductive coating 36 is thin (e.g., thinner than the first electricalconductor 32), the second electrical conductor 34 can be made to coverthe electrically conductive coating 36.

The present disclosure provides processes for making flexible electronicdevices (e.g., thermoelectric devices). The processes of fabricatingflexible electronic devices described herein can include a roll-to-roll(R2R) process, which can effectively reduce the thickness of electronicfilm devices, provide flexible, large-area electronic devices, andreduce the processing cost.

The operation of the present disclosure will be further described withregard to the following embodiments. These embodiments are offered tofurther illustrate the various specific and preferred embodiments andtechniques. It should be understood, however, that many variations andmodifications may be made while remaining within the scope of thepresent disclosure.

Listing of Exemplary Embodiments

-   It is to be understood that any one of embodiments 1-18, 19-25, and    26-27 can be combined.-   Embodiment 1 is a method comprising:

providing an array of solid semiconductor dies each extending between afirst end and an opposite, second end thereof;

sinking the first ends of the dies into a major surface of a firstliner;

filling a flowable polymeric material onto the major surface of thefirst liner;

solidifying the polymeric material to form a layer of polymeric matrixmaterial, wherein the array of solid semiconductor dies are at leastpartially embedded in the layer;

delaminating the first liner from the first ends of the dies; and

electrically connecting the first ends of the dies.

-   Embodiment 2 is the method of embodiment 1 further comprising    providing a second liner in contact with the array of dies at the    second ends thereof on the side opposite to the first liner.-   Embodiment 3 is the method of embodiment 1 or 2, wherein solidifying    the polymeric material comprises thermal or radiation curing.-   Embodiment 4 is the method of any one of embodiments 1-4 further    comprising electrically connecting the second ends of the array of    dies.-   Embodiment 5 is the method of embodiment 3 or 4, wherein the    polymeric material is cured from the side of the first ends, and an    uncured material at the second ends is removed after curing.-   Embodiment 6 is the method of any one of embodiments 1-5, wherein    filling the flowable polymeric material comprises filling the space    between the dies with the polymeric material by a capillary force.-   Embodiment 7 is the method of any one of embodiments 1-6, wherein    filling the flowable polymeric material comprises filling the space    between the dies by inkjet printing.-   Embodiment 8 is the method of any one of embodiments 1-7, further    comprising coating an electrically conductive, low-surface energy    material on the second ends of the array of dies on the side    opposite to the first liner.-   Embodiment 9 is the method of any one of embodiments 1-8, wherein    providing the array of dies comprises disposing the array of dies    into a pre-structured tooling, the second ends of the array of dies    project away from the pre-structured tooling.-   Embodiment 10 is the method of embodiment 9, wherein providing the    array of dies further comprises transferring the array of dies from    the pre-structured tooling onto an adhesive tape.-   Embodiment 11 is the method of embodiment 10, wherein providing the    array of dies further comprises transferring the array of dies from    the adhesive tape to the first liner.-   Embodiment 12 is the method of any one of embodiments 1-11, further    comprising melting the major surface of the first liner to allow the    first ends of the array of dies to sink into the major surface under    a pressure.-   Embodiment 13 is the method of embodiment 12, wherein the first ends    of the array of dies sink into the major surface of the first liner    with an average depth of about 0.5 to about 10 microns.-   Embodiment 14 is the method of any one of embodiments 1-13, wherein    the first liner has at least two layers, each layer having a    different melting point, such that the layer with the lower melting    point faces the array of dies; and further comprising heating the    layer with the lower melting point past a softening point thereof    such that the first ends of the dies are submerged in the layer with    the lower melting point.-   Embodiment 15 is the method of embodiment 14, wherein the first    liner comprises a layer of polyethylene phthalate and a layer of    polyethylene as the layer with the lower melting point.-   Embodiment 16 is the method of embodiment 12, further comprising    re-solidifying the major surface of the first liner to anchor the    array of dies thereon.-   Embodiment 17 is the method according to embodiment 3, wherein the    flowable polymeric material includes a polyurethane acrylate, a    polydimethylsiloxane, or a polyurethane rubber.-   Embodiment 18 is the method according to any one of embodiments    1-17, further comprising cleaning the first ends of the dies prior    to electrically connecting the first ends of the dies.-   Embodiment 19 is an electronic film device comprising:

a layer of polymer matrix material, the layer having opposite first andsecond major surfaces;

an array of solid semiconductor dies being at least partially embeddedin the layer, the dies each extending between a first end and a secondend thereof, the first ends projecting away from the first major surfaceof the layer; and

a first electrical conductor connecting the first ends of the array ofdies.

-   Embodiment 20 is the electronic film device of embodiment 19 further    comprises a second electrical conductor connecting the second ends    of the array of thermoelectric chips.-   Embodiment 21 is the electronic film device of embodiment 20,    wherein the first or second electrical conductor has a least a    portion directly disposed on the first or second major surface of    the layer.-   Embodiment 22 is the electronic film device of any one of    embodiments 19-21, wherein the layer of polymer matrix material is a    curing product of a curable polymeric material.-   Embodiment 23 is the electronic film device of embodiment 22,    wherein the curable polymeric material includes a polyurethane    acrylate, a polydimethylsiloxane, or a polyurethane rubber.-   Embodiment 24 is the electronic film device of any one of    embodiments 19-23, wherein the layer of polymer matrix material is a    flexible layer.-   Embodiment 25 is the electronic film device of any one of    embodiments 19-24, wherein the array of solid semiconductor dies    includes an n-type thermoelectric die and a p-type thermoelectric    die.-   Embodiment 26 is a flexible thermoelectric module comprising:

a layer of flexible polymer material, the layer having opposite firstand second major surfaces;

an array of solid thermoelectric dies being at least partially embeddedin the layer, the dies each extending between a first end and a secondend thereof, both ends being exposed from the layer of flexible polymermaterial, at least one of the first and second ends projecting away fromthe layer;

a first electrical conductor extending on the first major surface of thelayer to connect the first ends of the array of dies; and

a second electrical conductor extending on the first major surface ofthe layer to connect the second ends of the array of dies.

-   Embodiment 27 is the flexible thermoelectric module of embodiment    26, wherein the first ends of the dies project away from the first    major surface of the layer.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment,” whether ornot including the term “exemplary” preceding the term “embodiment,”means that a particular feature, structure, material, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the certain exemplary embodiments of the presentdisclosure. Thus, the appearances of the phrases such as “in one or moreembodiments,” “in certain embodiments,” “in one embodiment” or “in anembodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the certain exemplaryembodiments of the present disclosure. Furthermore, the particularfeatures, structures, materials, or characteristics may be combined inany suitable manner in one or more embodiments.

While the specification has described in detail certain exemplaryembodiments, it will be appreciated that those skilled in the art, uponattaining an understanding of the foregoing, may readily conceive ofalterations to, variations of, and equivalents to these embodiments.

Accordingly, it should be understood that this disclosure is not to beunduly limited to the illustrative embodiments set forth hereinabove. Inparticular, as used herein, the recitation of numerical ranges byendpoints is intended to include all numbers subsumed within that range(e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). In addition,all numbers used herein are assumed to be modified by the term “about.”

Furthermore, all publications and patents referenced herein areincorporated by reference in their entirety to the same extent as ifeach individual publication or patent was specifically and individuallyindicated to be incorporated by reference. Various exemplary embodimentshave been described. These and other embodiments are within the scope ofthe following claims.

1. A method comprising: providing an array of solid semiconductor dieseach extending between a first end and an opposite, second end thereof;sinking the first ends of the dies into a major surface of a firstliner; filling a flowable polymeric material onto the major surface ofthe first liner; solidifying the polymeric material to form a layer ofpolymeric matrix material, wherein the array of solid semiconductor diesis at least partially embedded in the layer of polymeric matrixmaterial; delaminating the first liner from the first ends of the dies;and electrically connecting the first ends of the dies.
 2. The method ofclaim 1 further comprising providing a second liner in contact with thearray of dies at the second ends thereof on the side opposite to thefirst liner.
 3. The method of claim 1, wherein solidifying the polymericmaterial comprises thermal or radiation curing.
 4. The method of claim 1further comprising electrically connecting the second ends of the arrayof dies.
 5. The method of claim 3, wherein the polymeric material iscured from the side of the first ends, and an uncured material at thesecond ends is removed after curing.
 6. The method of claim 1 furthercomprising coating an electrically conductive, low-surface energymaterial on the second ends of the array of dies on the side opposite tothe first liner.
 7. The method of claim 1, wherein providing the arrayof dies comprises disposing the array of dies into a pre-structuredtooling, the second ends of the array of dies project away from thepre-structured tooling.
 8. The method of claim 1 further comprisingmelting the major surface of the first liner to allow the first ends ofthe array of dies to sink into the major surface under a pressure. 9.The method of claim 1, wherein the first liner has at least two layers,each layer having a different melting point, such that the layer withthe lower melting point faces the array of dies; and further comprisingheating the layer with the lower melting point past a softening pointthereof such that the first ends of the dies are submerged in the layerwith the lower melting point.
 10. The method of claim 9, wherein thefirst liner comprises a layer of polyethylene phthalate and a layer ofpolyethylene as the layer with the lower melting point.
 11. The methodaccording to claim 3, wherein the flowable polymeric material includes apolyurethane acrylate, a polydimethylsiloxane, or a polyurethane rubber.12. An electronic film device comprising: a layer of polymer matrixmaterial, the layer having opposite first and second major surfaces; anarray of solid semiconductor dies being at least partially embedded inthe layer, the dies each extending between a first end and a second endthereof, the first ends projecting away from the first major surface ofthe layer; and a first electrical conductor connecting the first ends ofthe array of dies.
 13. The electronic film device of claim 12 furthercomprising a second electrical conductor connecting the second ends ofthe array of thermoelectric chips.
 14. The electronic film device ofclaim 13, wherein the first or second electrical conductor has a least aportion directly disposed on the first or second major surface of thelayer.
 15. The electronic film device of claim 12, wherein the layer ofpolymer matrix material is a curing product of a curable polymericmaterial.
 16. The electronic film device of claim 15, wherein thecurable polymeric material includes a polyurethane acrylate, apolydimethylsiloxane, or a polyurethane rubber.
 17. The electronic filmdevice of claim 12, wherein the layer of polymer matrix material is aflexible layer.
 18. The electronic film device of claim 12, wherein thearray of solid semiconductor dies includes at least one n-typethermoelectric die and at least one p-type thermoelectric die.
 19. Aflexible thermoelectric module comprising: a layer of flexible polymermaterial, the layer having opposite first and second major surfaces; anarray of solid thermoelectric dies being at least partially embedded inthe layer, the dies each extending between a first end and a second endthereof, both ends being exposed from the layer of flexible polymermaterial, at least one of the first and second ends projecting away fromthe layer; a first electrical conductor extending on the first majorsurface of the layer to connect the first ends of the array of dies; anda second electrical conductor extending on the first major surface ofthe layer to connect the second ends of the array of dies.
 20. Theflexible thermoelectric module of claim 19, wherein the first ends ofthe dies project away from the first major surface of the layer.